reverted:
--- b/core/modules/comment/src/Plugin/migrate/destination/EntityComment.php
+++ a/core/modules/comment/src/Plugin/migrate/destination/EntityComment.php
@@ -5,7 +5,6 @@
 use Drupal\Core\Entity\EntityManagerInterface;
 use Drupal\Core\Entity\EntityStorageInterface;
 use Drupal\Core\Field\FieldTypePluginManagerInterface;
-use Drupal\Core\Language\LanguageManagerInterface;
 use Drupal\Core\State\StateInterface;
 use Drupal\migrate\Plugin\MigrationInterface;
 use Drupal\migrate\Plugin\migrate\destination\EntityContentBase;
@@ -48,8 +47,6 @@
    *   The storage for this entity type.
    * @param array $bundles
    *   The list of bundles this entity type has.
-   * @param LanguageManagerInterface $language_manager
-   *   The language manager.
    * @param \Drupal\Core\Entity\EntityManagerInterface $entity_manager
    *   The entity manager service.
    * @param \Drupal\Core\Field\FieldTypePluginManagerInterface $field_type_manager
@@ -57,8 +54,8 @@
    * @param \Drupal\Core\State\StateInterface $state
    *   The state storage object.
    */
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, EntityStorageInterface $storage, array $bundles, EntityManagerInterface $entity_manager, FieldTypePluginManagerInterface $field_type_manager, StateInterface $state) {
+    parent::__construct($configuration, $plugin_id, $plugin_definition, $migration, $storage, $bundles, $entity_manager, $field_type_manager);
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, EntityStorageInterface $storage, array $bundles, LanguageManagerInterface $language_manager, EntityManagerInterface $entity_manager, FieldTypePluginManagerInterface $field_type_manager, StateInterface $state) {
-    parent::__construct($configuration, $plugin_id, $plugin_definition, $migration, $storage, $bundles, $language_manager, $entity_manager, $field_type_manager);
     $this->state = $state;
   }
 
@@ -74,7 +71,6 @@
       $migration,
       $container->get('entity.manager')->getStorage($entity_type),
       array_keys($container->get('entity.manager')->getBundleInfo($entity_type)),
-      $container->get('language_manager'),
       $container->get('entity.manager'),
       $container->get('plugin.manager.field.field_type'),
       $container->get('state')
reverted:
--- b/core/modules/config_translation/migration_templates/d6_i18n_block.yml
+++ /dev/null
@@ -1,68 +0,0 @@
-id: d6_i18n_block
-label: i18n Blocks
-migration_tags:
-  - Drupal 6
-source:
-  plugin: d6_i18n_block
-  constants:
-    dest_label: 'settings/label'
-process:
-  langcode: language
-  property: constants/dest_label
-  translation: translation
-  id:
-    -
-      plugin: concat
-      source:
-        - module
-        - objectid
-      delimiter: _
-    -
-      plugin: substr
-      length: 32
-  plugin:
-    -
-      plugin: static_map
-      bypass: true
-      source:
-        - module
-        - delta
-      map:
-        book:
-          0: book_navigation
-        comment:
-          0: views_block:comments_recent-block_1
-        forum:
-          0: forum_active_block
-          1: forum_new_block
-        locale:
-          0: language_block
-        node:
-          0: node_syndicate_block
-        search:
-          0: search_form_block
-        statistics:
-          0: statistics_popular_block
-        system:
-          0: system_powered_by_block
-        user:
-          0: user_login_block
-          1: system_menu_block:tools
-          2: views_block:who_s_new-block_1
-          3: views_block:who_s_online-who_s_online_block
-    -
-      plugin: block_plugin_id
-    -
-      plugin: skip_on_empty
-      method: row
-  theme:
-    plugin: block_theme
-    source:
-      - theme
-      - default_theme
-      - admin_theme
-destination:
-  plugin: entity:block
-migration_dependencies:
-  required:
-    - d6_block
reverted:
--- b/core/modules/config_translation/src/Plugin/migrate/process/I18nBlockSettings.php
+++ /dev/null
@@ -1,35 +0,0 @@
-<?php
-
-namespace Drupal\config_translation\Plugin\migrate\process;
-
-use Drupal\block\BlockInterface;
-use Drupal\migrate\MigrateExecutableInterface;
-use Drupal\migrate\ProcessPluginBase;
-use Drupal\migrate\Row;
-
-/**
- * @MigrateProcessPlugin(
- *   id = "i18n_block_settings"
- * )
- */
-class I18nBlockSettings extends ProcessPluginBase {
-
-  /**
-   * {@inheritdoc}
-   *
-   * Set the block configuration.
-   */
-  public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
-    list($plugin, $delta, $old_settings, $title) = $value;
-    $settings = [];
-    $settings['label'] = $title;
-    if ($title) {
-      $settings['label_display'] = BlockInterface::BLOCK_LABEL_VISIBLE;
-    }
-    else {
-      $settings['label_display'] = '0';
-    }
-    return $settings;
-  }
-
-}
reverted:
--- b/core/modules/config_translation/src/Plugin/migrate/source/d6/I18nBlock.php
+++ /dev/null
@@ -1,103 +0,0 @@
-<?php
-
-namespace Drupal\config_translation\Plugin\migrate\source\d6;
-
-use Drupal\migrate\Row;
-use Drupal\migrate_drupal\Plugin\migrate\source\DrupalSqlBase;
-
-/**
- * Gets i18n string block data from source database.
- *
- * @MigrateSource(
- *   id = "d6_i18n_block",
- *   source_provider = "block"
- * )
- */
-class I18nBlock extends DrupalSqlBase {
-
-  /**
-   * The default theme name.
-   *
-   * @var string
-   */
-  protected $defaultTheme;
-
-  /**
-   * The admin theme name.
-   *
-   * @var string
-   */
-  protected $adminTheme;
-
-  /**
-   * Table containing block configuration.
-   *
-   * @var string
-   */
-  protected $blockTable;
-
-  /**
-   * {@inheritdoc}
-   */
-  public function query() {
-    if ($this->getModuleSchemaVersion('system') >= 7000) {
-      $this->blockTable = 'block';
-    }
-    else {
-      $this->blockTable = 'blocks';
-    }
-    $query = $this->select('i18n_strings', 'i18n')
-      ->fields('i18n', ['lid', 'type', 'property', 'objectid'])
-      ->fields('lt', ['lid', 'language', 'translation'])
-      ->fields('b', ['bid', 'module', 'delta', 'theme'])
-      ->condition('i18n.type', 'block');
-    $query->leftJoin($this->blockTable, 'b', 'b.bid = i18n.objectid');
-    $query->leftJoin('locales_target', 'lt', 'lt.lid = i18n.lid');
-    return $query;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function initializeIterator() {
-    $this->defaultTheme = $this->variableGet('theme_default', 'Garland');
-    $this->adminTheme = $this->variableGet('admin_theme', NULL);
-    return parent::initializeIterator();
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function fields() {
-    return [
-      'bid' => $this->t('The block numeric identifier.'),
-      'module' => $this->t('The module providing the block.'),
-      'delta' => $this->t("The block's delta."),
-      'theme' => $this->t('Which theme the block is placed in.'),
-      'language' => $this->t('Language for this field.'),
-      'property' => $this->t('Name of property being translated.'),
-      'translation' => $this->t('Translation of either the title or explanation.'),
-    ];
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getIds() {
-    $ids['module']['type'] = 'string';
-    $ids['delta']['type'] = 'string';
-    $ids['theme']['type'] = 'string';
-    $ids['language']['type'] = 'string';
-    return $ids;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function prepareRow(Row $row) {
-    $row->setSourceProperty('default_theme', $this->defaultTheme);
-    $row->setSourceProperty('admin_theme', $this->adminTheme);
-    return parent::prepareRow($row);
-  }
-
-}
reverted:
--- b/core/modules/config_translation/tests/src/Kernel/Migrate/d6/MigrateI18nBlockTest.php
+++ /dev/null
@@ -1,66 +0,0 @@
-<?php
-
-namespace Drupal\Tests\config_translation\Kernel\Migrate\d6;
-
-use Drupal\Tests\migrate_drupal\Kernel\d6\MigrateDrupal6TestBase;
-
-/**
- * Tests the migration of block title translation.
- *
- * @group migrate_drupal_6
- */
-class MigrateI18nBlockTest extends MigrateDrupal6TestBase {
-
-  /**
-   * {@inheritdoc}
-   */
-  public static $modules = [
-    'block',
-    'views',
-    'comment',
-    'menu_ui',
-    'block_content',
-    'config_translation',
-    'language',
-  ];
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function setUp() {
-    parent::setUp();
-    $this->installConfig(['block_content']);
-    $this->installEntitySchema('block_content');
-
-    // Set Bartik and Seven as the default public and admin theme.
-    $config = $this->config('system.theme');
-    $config->set('default', 'bartik');
-    $config->set('admin', 'seven');
-    $config->save();
-
-    // Install one of D8's test themes.
-    \Drupal::service('theme_handler')->install(['test_theme']);
-
-    $this->executeMigrations([
-      'd6_filter_format',
-      'block_content_type',
-      'block_content_body_field',
-      'menu',
-      'd6_custom_block',
-      'd6_user_role',
-      'd6_block',
-      'd6_i18n_block',
-    ]);
-  }
-
-  /**
-   * Tests the migration of block title translation.
-   */
-  public function testI18nBlock() {
-    $config = \Drupal::service('language_manager')->getLanguageConfigOverride('fr', 'block.block.user');
-    $this->assertSame('fr - Static Block', $config->get('settings.label'));
-    $config = \Drupal::service('language_manager')->getLanguageConfigOverride('fr', 'block.block.user_1');
-    $this->assertSame('Encore un bloc statique', $config->get('settings.label'));
-  }
-
-}
reverted:
--- b/core/modules/config_translation/tests/src/Kernel/Plugin/migrate/source/d6/I18nBlockSourceTest.php
+++ /dev/null
@@ -1,157 +0,0 @@
-<?php
-
-namespace Drupal\Tests\config_translation\Kernel\Plugin\migrate\source\d6;
-
-use Drupal\Tests\migrate\Kernel\MigrateSqlSourceTestBase;
-
-/**
- * Tests i18n string block source plugin.
- *
- * @covers Drupal\config_translation\Plugin\migrate\source\d6\I18nBlock
- *
- * @group config_translation
- */
-class I18nBlockSourceTest extends MigrateSqlSourceTestBase {
-
-  /**
-   * {@inheritdoc}
-   */
-  public static $modules = ['config_translation', 'migrate_drupal'];
-
-  /**
-   * {@inheritdoc}
-   */
-  public function providerSource() {
-    $tests = [];
-
-    // The source data.
-    $tests[0]['database']['blocks'] = [
-      [
-        'bid' => 1,
-        'module' => 'block',
-        'delta' => '1',
-        'theme' => 'garland',
-        'status' => 1,
-        'weight' => 0,
-        'region' => 'left',
-        'custom' => 0,
-        'throttle' => 0,
-        'visibility' => 1,
-        'pages' => '',
-        'title' => 'Test Title 01',
-        'cache' => -1,
-      ],
-      [
-        'bid' => 2,
-        'module' => 'block',
-        'delta' => '2',
-        'theme' => 'garland',
-        'status' => 1,
-        'weight' => 5,
-        'region' => 'right',
-        'custom' => 0,
-        'throttle' => 0,
-        'visibility' => 0,
-        'pages' => '<front>',
-        'title' => 'Test Title 02',
-        'cache' => -1,
-      ],
-    ];
-
-    $tests[0]['database']['i18n_strings'] = [
-      [
-        'lid' => 1,
-        'objectid' => 1,
-        'type' => 'block',
-        'property' => 'title',
-        'objectindex' => 0,
-        'format' => 0,
-      ],
-      [
-        'lid' => 2,
-        'objectid' => 1,
-        'type' => 'block',
-        'property' => 'body',
-        'objectindex' => 0,
-        'format' => 0,
-      ],
-      [
-        'lid' => 3,
-        'objectid' => 2,
-        'type' => 'block',
-        'property' => 'body',
-        'objectindex' => 0,
-        'format' => 2,
-      ],
-    ];
-
-    $tests[0]['database']['locales_target'] = [
-      [
-        'lid' => 1,
-        'language' => 'fr',
-        'translation' => 'fr - title translation',
-        'plid' => 0,
-        'plural' => 0,
-        'u18n_status' => 0,
-      ],
-      [
-        'lid' => 2,
-        'language' => 'fr',
-        'translation' => 'fr - description translation',
-        'plid' => 0,
-        'plural' => 0,
-        'u18n_status' => 0,
-      ],
-      [
-        'lid' => 3,
-        'language' => 'zu',
-        'translation' => 'zu - description translation',
-        'plid' => 0,
-        'plural' => 0,
-        'u18n_status' => 0,
-      ],
-    ];
-
-    $tests[0]['expectedResults'] = [
-      [
-        'lid' => '1',
-        'type' => 'block',
-        'property' => 'title',
-        'objectid' => '1',
-        'lt_lid' => '1',
-        'language' => 'fr',
-        'translation' => 'fr - title translation',
-        'bid' => '1',
-        'module' => 'block',
-        'delta' => '1',
-      ],
-      [
-        'lid' => '2',
-        'type' => 'block',
-        'property' => 'body',
-        'objectid' => '1',
-        'lt_lid' => '2',
-        'language' => 'fr',
-        'translation' => 'fr - description translation',
-        'bid' => '1',
-        'module' => 'block',
-        'delta' => '1',
-      ],
-      [
-        'lid' => '3',
-        'type' => 'block',
-        'property' => 'body',
-        'objectid' => '2',
-        'lt_lid' => '3',
-        'language' => 'zu',
-        'translation' => 'zu - description translation',
-        'bid' => '2',
-        'module' => 'block',
-        'delta' => '2',
-      ],
-    ];
-
-    return $tests;
-  }
-
-}
diff -u b/core/modules/content_translation/tests/src/Kernel/Migrate/d6/MigrateI18nBlockContentTest.php b/core/modules/content_translation/tests/src/Kernel/Migrate/d6/MigrateI18nBlockContentTest.php
--- b/core/modules/content_translation/tests/src/Kernel/Migrate/d6/MigrateI18nBlockContentTest.php
+++ b/core/modules/content_translation/tests/src/Kernel/Migrate/d6/MigrateI18nBlockContentTest.php
@@ -2,24 +2,22 @@
 
 namespace Drupal\Tests\content_translation\Kernel\Migrate\d6;
 
-use Drupal\block_content\Entity\BlockContent;
-use Drupal\language\Entity\ConfigurableLanguage;
 use Drupal\Tests\migrate_drupal\Kernel\d6\MigrateDrupal6TestBase;
 
 /**
- * Tests migration of i18n custom block strings.
+ * Tests migration of i18n block translations.
  *
  * @group migrate_drupal_6
  */
-class MigrateI18nBlockContentTest extends MigrateDrupal6TestBase {
+class MigrateI18nBlockTest extends MigrateDrupal6TestBase {
 
   /**
    * {@inheritdoc}
    */
   public static $modules = [
     'block',
+    'views',
     'block_content',
-    'config_translation',
     'content_translation',
     'language',
   ];
@@ -29,46 +27,28 @@
    */
   protected function setUp() {
     parent::setUp();
+    $this->installConfig(['block']);
     $this->installConfig(['block_content']);
     $this->installEntitySchema('block_content');
-    ConfigurableLanguage::createFromLangcode('en')->save();
-    ConfigurableLanguage::createFromLangcode('fr')->save();
-    ConfigurableLanguage::createFromLangcode('zu')->save();
+
     $this->executeMigrations([
       'd6_filter_format',
       'block_content_type',
       'block_content_body_field',
       'd6_custom_block',
-      'd6_i18n_custom_block',
+      'd6_user_role',
+      'd6_block',
+      'd6_i18n_block',
     ]);
+    block_rebuild();
   }
 
   /**
-   * Tests the Drupal 6 i18n custom block strings to Drupal 8 migration.
+   * Tests the migration of block title translation.
    */
-  public function testBlockMigration() {
-    /** @var BlockContent $block */
-    $block = BlockContent::load(1)->getTranslation('fr');
-    $this->assertSame('fr - Static Block', $block->label());
-    $this->assertTrue(REQUEST_TIME <= $block->getChangedTime() && $block->getChangedTime() <= time());
-    $this->assertSame('fr', $block->language()->getId());
-    $this->assertSame('<h3>fr - My first custom block body</h3>', $block->body->value);
-    $this->assertSame('full_html', $block->body->format);
-
-    $block = BlockContent::load(1)->getTranslation('zu');
-    $this->assertSame('My block 1', $block->label());
-    $this->assertTrue(REQUEST_TIME <= $block->getChangedTime() && $block->getChangedTime() <= time());
-    $this->assertSame('zu', $block->language()->getId());
-    $this->assertSame('<h3>zu - My first custom block body</h3>', $block->body->value);
-    $this->assertSame('full_html', $block->body->format);
-
-    $block = BlockContent::load(2)->getTranslation('fr');
-    $this->assertSame('Encore un bloc statique', $block->label());
-    $this->assertTrue(REQUEST_TIME <= $block->getChangedTime() && $block->getChangedTime() <= time());
-    $this->assertSame('fr', $block->language()->getId());
-    $this->assertSame('Nom de vocabulaire beaucoup plus long que trente-deux caractères', $block->body->value);
-    $this->assertSame('full_html', $block->body->format);
-
+  public function testI18nBlock() {
+   $config = \Drupal::service('language_manager')->getLanguageConfigOverride('zu', 'block.block.user_1');
+    $this->assertSame('zu - Test Title 02', $config->get('settings.label'));
   }
 
 }
reverted:
--- b/core/modules/migrate/src/Plugin/migrate/destination/EntityContentBase.php
+++ a/core/modules/migrate/src/Plugin/migrate/destination/EntityContentBase.php
@@ -7,7 +7,6 @@
 use Drupal\Core\Entity\EntityManagerInterface;
 use Drupal\Core\Entity\EntityStorageInterface;
 use Drupal\Core\Field\FieldTypePluginManagerInterface;
-use Drupal\Core\Language\LanguageManagerInterface;
 use Drupal\Core\TypedData\TranslatableInterface;
 use Drupal\Core\TypedData\TypedDataInterface;
 use Drupal\migrate\Plugin\MigrationInterface;
@@ -22,13 +21,6 @@
 class EntityContentBase extends Entity {
 
   /**
-   * The language manager.
-   *
-   * @var \Drupal\Core\Language\LanguageManagerInterface
-   */
-  protected $languageManager;
-
-  /**
    * Entity manager.
    *
    * @var \Drupal\Core\Entity\EntityManagerInterface
@@ -57,18 +49,15 @@
    *   The storage for this entity type.
    * @param array $bundles
    *   The list of bundles this entity type has.
-   * @param LanguageManagerInterface $language_manager
-   *   The language manager.
    * @param \Drupal\Core\Entity\EntityManagerInterface $entity_manager
    *   The entity manager service.
    * @param \Drupal\Core\Field\FieldTypePluginManagerInterface $field_type_manager
    *   The field type plugin manager service.
    */
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, EntityStorageInterface $storage, array $bundles, EntityManagerInterface $entity_manager, FieldTypePluginManagerInterface $field_type_manager) {
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, EntityStorageInterface $storage, array $bundles, LanguageManagerInterface $language_manager, EntityManagerInterface $entity_manager, FieldTypePluginManagerInterface $field_type_manager) {
     parent::__construct($configuration, $plugin_id, $plugin_definition, $migration, $storage, $bundles);
     $this->entityManager = $entity_manager;
     $this->fieldTypeManager = $field_type_manager;
-    $this->languageManager = $language_manager;
   }
 
   /**
@@ -82,9 +71,7 @@
       $plugin_definition,
       $migration,
       $container->get('entity.manager')->getStorage($entity_type),
+      array_keys($container->get('entity.manager')->getBundleInfo($entity_type)),
-      array_keys($container->get('entity.manager')
-        ->getBundleInfo($entity_type)),
-      $container->get('language_manager'),
       $container->get('entity.manager'),
       $container->get('plugin.manager.field.field_type')
     );
@@ -93,7 +80,7 @@
   /**
    * {@inheritdoc}
    */
+  public function import(Row $row, array $old_destination_id_values = array()) {
-  public function import(Row $row, array $old_destination_id_values = []) {
     $this->rollbackAction = MigrateIdMapInterface::ROLLBACK_DELETE;
     $entity = $this->getEntity($row, $old_destination_id_values);
     if (!$entity) {
@@ -118,9 +105,9 @@
    * @return array
    *   An array containing the entity ID.
    */
+  protected function save(ContentEntityInterface $entity, array $old_destination_id_values = array()) {
-  protected function save(ContentEntityInterface $entity, array $old_destination_id_values = []) {
     $entity->save();
+    return array($entity->id());
-    return [$entity->id()];
   }
 
   /**
@@ -298,8 +285,8 @@
     $field_definition = $definitions[$key];
 
     return [
+      'type' => $field_definition->getType(),
+    ] + $field_definition->getSettings();
-        'type' => $field_definition->getType(),
-      ] + $field_definition->getSettings();
   }
 
 }
reverted:
--- b/core/modules/migrate/tests/src/Kernel/MigrateEntityContentBaseTest.php
+++ a/core/modules/migrate/tests/src/Kernel/MigrateEntityContentBaseTest.php
@@ -86,7 +86,6 @@
       $this->getMock(MigrationInterface::class),
       $this->storage,
       [],
-      $this->container->get('language_manager'),
       $this->container->get('entity.manager'),
       $this->container->get('plugin.manager.field.field_type')
     );
reverted:
--- b/core/modules/migrate/tests/src/Unit/Plugin/migrate/destination/EntityContentBaseTest.php
+++ a/core/modules/migrate/tests/src/Unit/Plugin/migrate/destination/EntityContentBaseTest.php
@@ -13,7 +13,6 @@
 use Drupal\Core\Entity\EntityStorageInterface;
 use Drupal\Core\Field\BaseFieldDefinition;
 use Drupal\Core\Field\FieldTypePluginManagerInterface;
-use Drupal\Core\Language\LanguageManagerInterface;
 use Drupal\migrate\Plugin\MigrationInterface;
 use Drupal\migrate\Plugin\migrate\destination\EntityContentBase;
 use Drupal\migrate\Plugin\MigrateIdMapInterface;
@@ -44,13 +43,6 @@
   protected $entityManager;
 
   /**
-   * The language manager.
-   *
-   * @var \Drupal\Core\Language\LanguageManagerInterface
-   */
-  protected $languageManager;
-
-  /**
    * {@inheritdoc}
    */
   protected function setUp() {
@@ -59,7 +51,6 @@
     $this->migration = $this->prophesize(MigrationInterface::class);
     $this->storage = $this->prophesize(EntityStorageInterface::class);
     $this->entityManager = $this->prophesize(EntityManagerInterface::class);
-    $this->languageManager = $this->prophesize(LanguageManagerInterface::class);
   }
 
   /**
@@ -73,7 +64,6 @@
       $this->migration->reveal(),
       $this->storage->reveal(),
       $bundles,
-      $this->languageManager->reveal(),
       $this->entityManager->reveal(),
       $this->prophesize(FieldTypePluginManagerInterface::class)->reveal());
     $entity = $this->prophesize(ContentEntityInterface::class);
@@ -103,7 +93,6 @@
       $this->migration->reveal(),
       $this->storage->reveal(),
       $bundles,
-      $this->languageManager->reveal(),
       $this->entityManager->reveal(),
       $this->prophesize(FieldTypePluginManagerInterface::class)->reveal());
     $destination->setEntity(FALSE);
@@ -133,7 +122,6 @@
       $this->migration->reveal(),
       $this->storage->reveal(),
       [],
-      $this->languageManager->reveal(),
       $this->entityManager->reveal(),
       $this->prophesize(FieldTypePluginManagerInterface::class)->reveal()
     );
reverted:
--- b/core/modules/migrate/tests/src/Unit/destination/EntityRevisionTest.php
+++ a/core/modules/migrate/tests/src/Unit/destination/EntityRevisionTest.php
@@ -9,7 +9,6 @@
 
 use Drupal\Core\Entity\ContentEntityInterface;
 use Drupal\Core\Entity\EntityInterface;
-use Drupal\Core\Language\LanguageManagerInterface;
 use Drupal\migrate\Plugin\MigrationInterface;
 use Drupal\migrate\Plugin\migrate\destination\EntityRevision as RealEntityRevision;
 use Drupal\migrate\Row;
@@ -43,13 +42,6 @@
    */
   protected $fieldTypeManager;
 
-  /**
-   * The language manager.
-   *
-   * @var \Drupal\Core\Language\LanguageManagerInterface
-   */
-  protected $languageManager;
-
   protected function setUp() {
     parent::setUp();
 
@@ -58,8 +50,6 @@
     $this->storage = $this->prophesize('\Drupal\Core\Entity\EntityStorageInterface');
     $this->entityManager = $this->prophesize('\Drupal\Core\Entity\EntityManagerInterface');
     $this->fieldTypeManager = $this->prophesize('\Drupal\Core\Field\FieldTypePluginManagerInterface');
-    $this->languageManager = $this->prophesize(LanguageManagerInterface::class);
-
   }
 
   /**
@@ -200,7 +190,6 @@
       $this->migration->reveal(),
       $this->storage->reveal(),
       [],
-      $this->languageManager->reveal(),
       $this->entityManager->reveal(),
       $this->fieldTypeManager->reveal()
     );
reverted:
--- b/core/modules/migrate_drupal/src/Plugin/migrate/destination/EntityFieldStorageConfig.php
+++ a/core/modules/migrate_drupal/src/Plugin/migrate/destination/EntityFieldStorageConfig.php
@@ -26,13 +26,6 @@
 class EntityFieldStorageConfig extends BaseEntityFieldStorageConfig {
 
   /**
-   * The language manager.
-   *
-   * @var \Drupal\Core\Language\LanguageManagerInterface
-   */
-  protected $languageManager;
-
-  /**
    * The field type plugin manager.
    *
    * @var \Drupal\Core\Field\FieldTypePluginManagerInterface
diff -u b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
--- b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
+++ b/core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeForm.php
@@ -67,8 +67,8 @@
       'destination_module' => 'block',
     ],
     'd6_i18n_block' => [
-      'source_module' => 'translation',
-      'destination_module' => 'config_translation',
+      'source_module' => 'i18n',
+      'destination_module' => 'content_translation',
     ],
     'd7_block' => [
       'source_module' => 'block',
reverted:
--- b/core/modules/user/src/Plugin/migrate/destination/EntityUser.php
+++ a/core/modules/user/src/Plugin/migrate/destination/EntityUser.php
@@ -8,7 +8,6 @@
 use Drupal\Core\Entity\EntityStorageInterface;
 use Drupal\Core\Field\FieldTypePluginManagerInterface;
 use Drupal\Core\Field\Plugin\Field\FieldType\EmailItem;
-use Drupal\Core\language\LanguageManagerInterface;
 use Drupal\Core\Password\PasswordInterface;
 use Drupal\migrate\Plugin\MigrationInterface;
 use Drupal\migrate\Plugin\migrate\destination\EntityContentBase;
@@ -44,8 +43,6 @@
    *   The storage for this entity type.
    * @param array $bundles
    *   The list of bundles this entity type has.
-   * @param \Drupal\Core\language\LanguageManagerInterface $language_manager
-   *   The language manager service.
    * @param \Drupal\Core\Entity\EntityManagerInterface $entity_manager
    *   The entity manager service.
    * @param \Drupal\Core\Field\FieldTypePluginManagerInterface $field_type_manager
@@ -53,8 +50,8 @@
    * @param \Drupal\Core\Password\PasswordInterface $password
    *   The password service.
    */
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, EntityStorageInterface $storage, array $bundles, EntityManagerInterface $entity_manager, FieldTypePluginManagerInterface $field_type_manager, PasswordInterface $password) {
+    parent::__construct($configuration, $plugin_id, $plugin_definition, $migration, $storage, $bundles, $entity_manager, $field_type_manager);
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, EntityStorageInterface $storage, array $bundles, LanguageManagerInterface $language_manager, EntityManagerInterface $entity_manager, FieldTypePluginManagerInterface $field_type_manager, PasswordInterface $password) {
-    parent::__construct($configuration, $plugin_id, $plugin_definition, $migration, $storage, $bundles, $language_manager, $entity_manager, $field_type_manager);
     $this->password = $password;
   }
 
@@ -70,7 +67,6 @@
       $migration,
       $container->get('entity.manager')->getStorage($entity_type),
       array_keys($container->get('entity.manager')->getBundleInfo($entity_type)),
-      $container->get('language_manager'),
       $container->get('entity.manager'),
       $container->get('plugin.manager.field.field_type'),
       $container->get('password')
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/content_translation/migration_templates/d6_i18n_block.yml
@@ -0,0 +1,71 @@
+id: d6_i18n_block
+label: i18n Blocks
+migration_tags:
+  - Drupal 6
+source:
+  plugin: d6_i18n_block
+  constants:
+    dest_label: 'settings/label'
+process:
+  langcode: language
+  property: constants/dest_label
+  translation: title
+  id:
+    -
+      plugin: concat
+      source:
+        - module
+        - delta
+      delimiter: _
+    -
+      plugin: substr
+      length: 32
+  configuration_name: @id
+  element_name: constance/dest_label
+  value: title
+  plugin:
+    -
+      plugin: static_map
+      bypass: true
+      source:
+        - module
+        - delta
+      map:
+        book:
+          0: book_navigation
+        comment:
+          0: views_block:comments_recent-block_1
+        forum:
+          0: forum_active_block
+          1: forum_new_block
+        locale:
+          0: language_block
+        node:
+          0: node_syndicate_block
+        search:
+          0: search_form_block
+        statistics:
+          0: statistics_popular_block
+        system:
+          0: system_powered_by_block
+        user:
+          0: user_login_block
+          1: system_menu_block:tools
+          2: views_block:who_s_new-block_1
+          3: views_block:who_s_online-who_s_online_block
+    -
+      plugin: block_plugin_id
+    -
+      plugin: skip_on_empty
+      method: row
+  theme:
+    plugin: block_theme
+    source:
+      - theme
+      - default_theme
+      - admin_theme
+destination:
+  plugin: entity:block
+migration_dependencies:
+  required:
+    - d6_block
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/content_translation/src/Plugin/migrate/source/d6/I18nBlock.php
@@ -0,0 +1,104 @@
+<?php
+
+namespace Drupal\content_translation\Plugin\migrate\source\d6;
+
+use Drupal\migrate\Row;
+use Drupal\migrate_drupal\Plugin\migrate\source\DrupalSqlBase;
+
+/**
+ * Gets i18n block data from source database.
+ *
+ * @MigrateSource(
+ *   id = "d6_i18n_block",
+ *   source_provider = "block"
+ * )
+ */
+class I18nBlock extends DrupalSqlBase {
+
+  /**
+   * The default theme name.
+   *
+   * @var string
+   */
+  protected $defaultTheme;
+
+  /**
+   * The admin theme name.
+   *
+   * @var string
+   */
+  protected $adminTheme;
+
+  /**
+   * Table containing block configuration.
+   *
+   * @var string
+   */
+  protected $blockTable;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function query() {
+    if ($this->getModuleSchemaVersion('system') >= 7000) {
+      $this->blockTable = 'block';
+    }
+    else {
+      $this->blockTable = 'blocks';
+    }
+
+    $query = $this->select('i18n_blocks', 'i18n')
+      ->fields('i18n', ['ibid', 'module', 'delta', 'type', 'language'])
+      ->fields('b', ['bid', 'module', 'delta', 'theme', 'title']);
+    $query->addField('b', 'module', 'block_module');
+    $query->addField('b', 'delta', 'block_delta');
+    $query->leftJoin($this->blockTable, 'b', ('b.module = i18n.module AND b.delta = i18n.delta'));
+    return $query;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function initializeIterator() {
+    $this->defaultTheme = $this->variableGet('theme_default', 'Garland');
+    $this->adminTheme = $this->variableGet('admin_theme', NULL);
+    return parent::initializeIterator();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function fields() {
+    return [
+      'bid' => $this->t('The block numeric identifier.'),
+      'module' => $this->t('The module providing the block.'),
+      'delta' => $this->t("The block's delta."),
+      'title' => $this->t("Title translation for this language.."),
+      'theme' => $this->t('Which theme the block is placed in.'),
+      'language' => $this->t('Language for this field.'),
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getIds() {
+    $ids['module']['type'] = 'string';
+    $ids['module']['alias'] = 'b';
+    $ids['delta']['type'] = 'string';
+    $ids['delta']['alias'] = 'b';
+    $ids['theme']['type'] = 'string';
+    $ids['language']['type'] = 'string';
+    return $ids;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function prepareRow(Row $row) {
+    $row->setSourceProperty('default_theme', $this->defaultTheme);
+    $row->setSourceProperty('admin_theme', $this->adminTheme);
+    return parent::prepareRow($row);
+  }
+
+}
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/content_translation/tests/src/Kernel/Migrate/d6/MigrateI18nCustomBlockContentTest.php
@@ -0,0 +1,73 @@
+<?php
+
+namespace Drupal\Tests\content_translation\Kernel\Migrate\d6;
+
+use Drupal\block_content\Entity\BlockContent;
+use Drupal\language\Entity\ConfigurableLanguage;
+use Drupal\Tests\migrate_drupal\Kernel\d6\MigrateDrupal6TestBase;
+
+/**
+ * Tests migration of i18n custom block strings.
+ *
+ * @group migrate_drupal_6
+ */
+class MigrateI18nCustomBlockContentTest extends MigrateDrupal6TestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = [
+    'block',
+    'block_content',
+    'config_translation',
+    'content_translation',
+    'language',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+    $this->installConfig(['block_content']);
+    $this->installEntitySchema('block_content');
+    ConfigurableLanguage::createFromLangcode('en')->save();
+    ConfigurableLanguage::createFromLangcode('fr')->save();
+    ConfigurableLanguage::createFromLangcode('zu')->save();
+    $this->executeMigrations([
+      'd6_filter_format',
+      'block_content_type',
+      'block_content_body_field',
+      'd6_custom_block',
+      'd6_i18n_custom_block',
+    ]);
+  }
+
+  /**
+   * Tests the Drupal 6 i18n custom block strings to Drupal 8 migration.
+   */
+  public function testBlockMigration() {
+    /** @var BlockContent $block */
+    $block = BlockContent::load(1)->getTranslation('fr');
+    $this->assertSame('fr - Static Block', $block->label());
+    $this->assertTrue(REQUEST_TIME <= $block->getChangedTime() && $block->getChangedTime() <= time());
+    $this->assertSame('fr', $block->language()->getId());
+    $this->assertSame('<h3>fr - My first custom block body</h3>', $block->body->value);
+    $this->assertSame('full_html', $block->body->format);
+
+    $block = BlockContent::load(1)->getTranslation('zu');
+    $this->assertSame('My block 1', $block->label());
+    $this->assertTrue(REQUEST_TIME <= $block->getChangedTime() && $block->getChangedTime() <= time());
+    $this->assertSame('zu', $block->language()->getId());
+    $this->assertSame('<h3>zu - My first custom block body</h3>', $block->body->value);
+    $this->assertSame('full_html', $block->body->format);
+
+    $block = BlockContent::load(2)->getTranslation('fr');
+    $this->assertSame('Encore un bloc statique', $block->label());
+    $this->assertTrue(REQUEST_TIME <= $block->getChangedTime() && $block->getChangedTime() <= time());
+    $this->assertSame('fr', $block->language()->getId());
+    $this->assertSame('Nom de vocabulaire beaucoup plus long que trente-deux caractères', $block->body->value);
+    $this->assertSame('full_html', $block->body->format);
+  }
+
+}
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/content_translation/tests/src/Kernel/Plugin/migrate/source/d6/I18nBlockTest.php
@@ -0,0 +1,100 @@
+<?php
+
+namespace Drupal\Tests\content_translation\Kernel\Plugin\migrate\source\d6;
+
+use Drupal\Tests\migrate\Kernel\MigrateSqlSourceTestBase;
+
+/**
+ * Tests i18n block title source plugin.
+ *
+ * @covers Drupal\content_translation\Plugin\migrate\source\d6\I18nBlock
+ *
+ * @group content_translation
+ */
+class I18nBlockTest extends MigrateSqlSourceTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['content_translation', 'migrate_drupal'];
+
+  /**
+   * {@inheritdoc}
+   */
+  public function providerSource() {
+    $tests = [];
+
+    // The source data.
+    $tests[0]['source_data']['blocks'] = [
+      [
+        'bid' => 1,
+        'module' => 'user',
+        'delta' => '1',
+        'theme' => 'garland',
+        'status' => 1,
+        'weight' => 0,
+        'region' => 'left',
+        'visibility' => 0,
+        'pages' => '',
+        'title' => 'fr - Test Title 01',
+        'cache' => -1,
+      ],
+      [
+        'bid' => 2,
+        'module' => 'user',
+        'delta' => '2',
+        'theme' => 'garland',
+        'status' => 1,
+        'weight' => 5,
+        'region' => 'right',
+        'visibility' => 0,
+        'pages' => '<front>',
+        'title' => 'zu - Test Title 02',
+        'cache' => -1,
+      ],
+    ];
+
+    $tests[0]['source_data']['i18n_blocks'] = [
+      [
+        'ibid' => 1,
+        'module' => 'user',
+        'delta' => '1',
+        'type' => 0,
+        'language' => 'fr',
+      ],
+      [
+        'ibid' => 2,
+        'module' => 'user',
+        'delta' => '2',
+        'type' => 0,
+        'language' => 'zu',
+      ],
+    ];
+
+    // The expected results.
+    $tests[0]['expected_results'] = [
+      [
+        'bid' => 1,
+        'module' => 'user',
+        'delta' => '1',
+        'title' => 'fr - Test Title 01',
+        'ibid' => 1,
+        'type' => '0',
+        'language' => 'fr',
+      ],
+      [
+        'bid' => 2,
+        'module' => 'user',
+        'delta' => '2',
+        'theme' => 'garland',
+        'title' => 'zu - Test Title 02',
+        'ibid' => 2,
+        'type' => '0',
+        'language' => 'zu',
+      ],
+    ];
+
+    return $tests;
+  }
+
+}
only in patch2:
unchanged:
--- a/core/modules/migrate_drupal/tests/fixtures/drupal6.php
+++ b/core/modules/migrate_drupal/tests/fixtures/drupal6.php
@@ -662,7 +662,7 @@
   'throttle' => '0',
   'visibility' => '0',
   'pages' => '',
-  'title' => '',
+  'title' => 'zu - Test Title 02',
   'cache' => '-1',
 ))
 ->values(array(
@@ -8086,6 +8086,23 @@
   'mysql_character_set' => 'utf8',
 ));
 
+$connection->insert('i18n_blocks')
+->fields(array(
+  'ibid',
+  'module',
+  'delta',
+  'type',
+  'language',
+))
+->values(array(
+  'ibid' => '1',
+  'module' => 'user',
+  'delta' => '1',
+  'type' => '0',
+  'language' => 'zu',
+))
+->execute();
+
 $connection->schema()->createTable('i18n_strings', array(
   'fields' => array(
     'lid' => array(